The present invention relates generally to rocket propulsion systems, and more specifically to low temperature composite polar boss for use in place of metal for rocket motor polar bosses.
Development and production for solid rocket motors can be seriously affected by the long acquistion lead times for the conventional forged metal polar bosses used in composite motor cases. In addition, the long lead times for forged tooling severely restrict needed development program flexibility in making design changes. As an example, the development program for the inertial upper stage (IUS) solid rocket motors, had lead times of over a year for the closed-die forgings.
The task of providing an alternative to metal for rocket motor polar bosses, particularly for rockets with low temperature operating parameters, is alleviated, to some extent, by the systems disclosed in the following U.S. Patents, the disclosures of which are incorporated by reference;
U.S. Pat. No. 3,952,664 issued to Schmidt et al;
U.S. Pat. No. 4,421,806 issued to Marks et al;
U.S. Pat. No. 4,438,858 issued to Grover;
U.S. Pat. No. 4,581,263 issued to Lukas;
U.S. Pat. No. 4,585,136 issued to Clark; and
U.S. Pat. No. 4,588,622 issued to Sukarie.
Schmidt et al disclose a rocket motor assembly formed by a casing and a unitary nozzle igniter housing portion. The nozzle and ignitor housing portion has a circumferential portion that mates with the internal surface wall of the casing. A seal and fastener holds the housing in place. Grover shows a polar boss in FIGS. 2 and 4.
Clark is concerned with an arrangement for the attachment of an end ring to the body wall of a rocket motor case. The cylindrical wall in the vicinity of metal end ring in Clark is made up of a plurality of layers of three different kinds, the first kind being laid layer having the fibers extending primarily longitudinally i.e., parallel with the axis of the motor case; under this there may be a larger produced by polar winding, and thus also having the fibers extending primarily longitudinally; and then a layer produced by hoop winding.
Sukarie shows in FIGS. 2 and 3 a pressure container of carbon fibers joined to aluminum connection pieces. Lukas teaches a composite formed of carbon fiber in a graphite support matrix. Filament wound composite resin-fiber rocket motor cases form a part of the disclosure in the Marks et al patent.
Since the introduction of carbon-carbon materials into solid rocket motor nozzles, the number of parts making up the nozzle has decreased dramatically, resulting in a much simpler structure. The above-cited Plotzker et al reference is a state-of-the-art process for fabricating carbon-carbon articles. However, while the above-cited references are all instructive, the need remains to provide an alternative to metal for the polar bosses or rocket motors with low operating temperatures, the present invention is intended to satisfy that need.